In recent years, a light emitting device that is a combination of a solid-state light emitting element that emits laser light and a wavelength converter containing a phosphor has been proposed. There is a light emitting device formed of a solid-state light emitting element and a phosphor combined with each other with the wavelength or spectrum of the emitted light changed to a desired wavelength in accordance with the application.
When the phosphor is excited with the laser light having high light density, however, the phosphor experiences efficiency saturation, and the conversion efficiency of the phosphor therefore greatly falls. Therefore, undesirably, the power of the light emitting device cannot be sufficiently increased. For example, PTL 1 describes that a red phosphor tends to experience the efficiency saturation.
To address the problem described above, PTL 2 proposes a configuration in which light emitted from a semiconductor element is diffused by an optical lens and then applied to a wavelength converter containing a red phosphor for reduction in the light density of the light applied to the wavelength converter.